Which hand signal indicates a driver wants to slow down or stop?

The indication that a driver wants to slow down or stop is effectively communicated through the left hand and arm pointing downward at a 90-degree angle. This hand signal is universally recognized among motorcyclists and drivers as a way to alert others of a decrease in speed or the intention to come to a stop. It ensures that those following the vehicle are aware of the driver's actions, enhancing safety for everyone on the road. This gesture is particularly important in situations where brake lights may not be visible or when approaching a stop in a group ride scenario.

In contrast, the other signals represent different intentions. Extending the left arm outward points to the left, while bending the right arm at a 90-degree angle with the palm facing backward suggests that the driver intends to slow down, which is less commonly used than the hand signal with the arm pointing down. Finally, extending the right arm outward to signal a right turn does not convey any indication of slowing down or stopping. Hence, the downward signal is the clear and standardized method for communicating the intent to reduce speed or come to a halt.